<?php
/**
 * Conservative, per-feature ownership detection.
 *
 * Never deactivates another plugin and never inspects or buffers its HTML.
 * Full SEO suites still suppress every STS SEO feature. Jetpack is handled per
 * feature through its own documented filters (see sts_seo_jetpack_open_graph()).
 *
 * @package STS_SEO
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * The output features STS SEO can provide.
 *
 * @return string[] Feature keys.
 */
function sts_seo_features() {
	return array( 'title', 'description', 'social', 'posts_canonical', 'schema' );
}

/**
 * Detect active full SEO suites once per request.
 *
 * @return string[] Human-readable names.
 */
function sts_seo_detected_suites() {
	static $found = null;
	if ( null !== $found ) {
		return $found;
	}
	$known  = array(
		'wordpress-seo'           => 'Yoast SEO',
		'wordpress-seo-premium'   => 'Yoast SEO Premium',
		'seo-by-rank-math'        => 'Rank Math',
		'all-in-one-seo-pack'     => 'All in One SEO',
		'all-in-one-seo-pack-pro' => 'All in One SEO Pro',
		'wp-seopress'             => 'SEOPress',
		'autodescription'         => 'The SEO Framework',
		'slim-seo'                => 'Slim SEO',
	);
	$active = (array) get_option( 'active_plugins', array() );
	if ( is_multisite() ) {
		$active = array_merge( $active, array_keys( (array) get_site_option( 'active_sitewide_plugins', array() ) ) );
	}
	$found = array();
	foreach ( $active as $file ) {
		$slug = strtok( (string) $file, '/' );
		if ( isset( $known[ $slug ] ) ) {
			$found[] = $known[ $slug ];
		}
	}
	$constants = array(
		'WPSEO_VERSION'             => 'Yoast SEO',
		'RANK_MATH_VERSION'         => 'Rank Math',
		'AIOSEO_VERSION'            => 'All in One SEO',
		'SEOPRESS_VERSION'          => 'SEOPress',
		'THE_SEO_FRAMEWORK_VERSION' => 'The SEO Framework',
		'SLIM_SEO_VER'              => 'Slim SEO',
	);
	foreach ( $constants as $constant => $name ) {
		if ( defined( $constant ) ) {
			$found[] = $name;
		}
	}
	$found = array_values( array_unique( $found ) );
	return $found;
}

/**
 * List metadata owners that suppress every STS SEO feature.
 *
 * Unchanged contract since 0.1: a non-empty result turns all frontend output
 * off. Since 0.3.0 Jetpack is no longer listed here; it is handled per feature.
 *
 * @return string[] Human-readable names.
 */
function sts_seo_conflicts() {
	/**
	 * Filter detected providers; integrations may add a custom metadata owner.
	 *
	 * @param string[] $found Names of active full SEO suites.
	 */
	$found = apply_filters( 'sts_seo_conflicts', sts_seo_detected_suites() );
	return is_array( $found ) ? array_values( array_filter( $found, 'is_string' ) ) : array( 'Unknown metadata provider' );
}

/**
 * Whether the site keeps Jetpack's own social tags instead of STS SEO's.
 *
 * @return bool True when STS SEO should manage social tags (default).
 */
function sts_seo_manages_jetpack_social() {
	/**
	 * Filter whether STS SEO, rather than Jetpack, outputs social sharing tags.
	 *
	 * Return false to keep Jetpack's Open Graph and Twitter Card tags; STS SEO
	 * then skips its own social tags wherever Jetpack outputs them.
	 *
	 * @param bool $manage Default true.
	 */
	return (bool) apply_filters( 'sts_seo_jetpack_social', true );
}

/**
 * Features currently provided by Jetpack, which STS SEO therefore leaves alone.
 *
 * Uses only Jetpack's public module check and its documented filters.
 *
 * @return string[] Feature keys.
 */
function sts_seo_jetpack_features() {
	if ( ! class_exists( 'Jetpack' ) || ! is_callable( array( 'Jetpack', 'is_module_active' ) ) ) {
		return array();
	}
	$owned = array();
	// phpcs:disable WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- Reading Jetpack's documented filters.
	if ( Jetpack::is_module_active( 'seo-tools' ) && ! apply_filters( 'jetpack_disable_seo_tools', false ) ) {
		if ( apply_filters( 'jetpack_seo_custom_titles', true ) ) {
			$owned[] = 'title';
		}
		if ( apply_filters( 'jetpack_seo_meta_tags_enabled', true ) ) {
			$owned[] = 'description';
		}
	}
	// Jetpack decides whether to load its Open Graph tags at wp_head priority 1.
	if ( ! sts_seo_manages_jetpack_social() && apply_filters( 'jetpack_enable_open_graph', false ) ) {
		$owned[] = 'social';
	}
	// phpcs:enable
	return $owned;
}

/**
 * The plugin that owns a feature instead of STS SEO, or '' when STS SEO does.
 *
 * @param string $feature Feature key from sts_seo_features().
 * @return string Owner name, or ''.
 */
function sts_seo_feature_owner( $feature ) {
	$owner = in_array( $feature, sts_seo_jetpack_features(), true ) ? 'Jetpack' : '';
	/**
	 * Filter which plugin owns a single STS SEO feature.
	 *
	 * Return a non-empty name to let another plugin provide that feature; STS
	 * SEO then skips only that output. Return '' to let STS SEO provide it.
	 *
	 * @param string $owner   Current owner name, or ''.
	 * @param string $feature One of title, description, social, posts_canonical, schema.
	 */
	$owner = apply_filters( 'sts_seo_feature_owner', $owner, $feature );
	return is_string( $owner ) ? $owner : 'Unknown metadata provider';
}

/**
 * Whether STS SEO should output a feature on this request.
 *
 * @param string $feature Feature key from sts_seo_features().
 * @return bool
 */
function sts_seo_feature_enabled( $feature ) {
	if ( ! apply_filters( 'sts_seo_enabled', true ) || sts_seo_conflicts() ) {
		return false;
	}
	return '' === sts_seo_feature_owner( $feature );
}

/**
 * Turn off Jetpack's Open Graph and Twitter Card tags where STS SEO outputs its own.
 *
 * Hooked to Jetpack's documented `jetpack_enable_open_graph` filter at priority
 * 100, after Jetpack's own defaults (0) and its conflict list (99). Applies only
 * on requests where STS SEO actually prints social tags (public Posts, Pages and
 * the posts index), so Jetpack keeps archives and other views. Nothing is stored:
 * deactivating STS SEO or returning false from `sts_seo_jetpack_social` restores
 * Jetpack's tags immediately.
 *
 * @param bool $enabled Whether Jetpack will output Open Graph tags.
 * @return bool
 */
function sts_seo_jetpack_open_graph( $enabled ) {
	if ( ! $enabled || is_admin() || ! sts_seo_manages_jetpack_social() || ! sts_seo_feature_enabled( 'social' ) ) {
		return $enabled;
	}
	return sts_seo_metadata() ? false : $enabled;
}